1. Field of the Invention
The present invention relates to a flexible printed circuit board and a bracket structure for a hard disk drive, and more particularly, to a flexible printed circuit board having a filter and a bracket structure.
2. Description of Related Art
A hard disk drive (HDD) is a memory unit to read data from a disk or write data to the disk using a read/write head. During operation of the hard disk drive, the read/write head is moved to a desired position by an actuator while being floated a certain distance above a recording surface of the disk.
The actuator is driven by a flexible printed circuit connected to a bracket, which will be described in detail with reference to FIG. 1.
FIG. 1 is a plan view of a conventional hard disk drive including a CSS (contact start stop) type head parking system.
Referring to FIG. 1, the hard disk drive includes a magnetic disk (hard disk) 20 which is a recording medium for recording data, a spindle motor 30 installed to a base member 10 for spinning the disk 20, an actuator 40 having a read/write head 41 for writing data to the disk 20 and reading the data from the disk 20, and a flexible printed circuit member 60 for driving the actuator 40.
A plurality of disks 20 are generally spaced apart from each other, and are rotated by the spindle motor 30. The disk 20 is provided with a parking zone 21 on an inner periphery of the disk. When a power is turned off, a slider 42 with the read/write head 41 mounted thereon is seated on the parking zone 21. A data zone 22 to be recorded with data is provided on an outside of the parking zone 21.
The actuator 40 includes a swing arm 46 pivoting around a pivot 47 installed on the base member 10. A suspension 44 is installed to one end of the swing arm 46 for elastically biasing the slider 42 with the read/write head 41 mounted thereon against a surface of the disk.
The actuator 40 is rotated by a voice coil motor (VCM) 50. The voice coil motor 50 includes a VCM coil 56 connected to the other end of the swing arm 46. Magnets (not shown) are disposed at upper and lower portions of the VCM coil 56 to be opposite to each other.
In the conventional hard disk drive configured as described above, a lift force caused by air flow generated by rotation of the disk 20 and an elastic force of the suspension 44 act on the slider 42 with the read/write head 41 mounted thereon, during writing or reading data. As such, the slider 42 is floated on the data zone 22 of the disk at a height at which the lift force and the elastic force are in balance. The head 41 mounted on the slider 42 writes the data to the disk 20 and reads the data from the disk 20, while the slider 42 is spaced apart from the rotating disk 20 at a constant interval.
The flexible printed circuit member 60 includes a flexible printed circuit board 70 for driving the actuator 40, and a bracket 61 supporting the flexible printed circuit board 70. The flexible printed circuit member 60 also includes a connector and a gasket.
The flexible printed circuit board 70 includes a conductive metal layer, a base layer, a circuit layer, and a cover layer, which are sequentially deposited, with an adhesive layer being interposed between the respective layers to adhere the layers. The connector is soldered to the flexible printed circuit board 70, and the gasket seals a space between the flexible printed circuit board 70 and the bracket 61.
The conductive metal layer reduces electromagnetic interference (EMI) against a bottom surface of the flexible printed circuit 70, and prevents deformation of the flexible printed circuit 70 during baking.
The circuit layer is provided with various circuits required for driving the actuator 40. In order to reduce a manufacturing cost and simplify a manufacturing process, after the circuit layer with circuits thereof interconnected is manufactured, the circuits are typically cut by mechanical punching so that the respective circuits are separated from one another. External air flows in the hard disk drive through holes formed by the punching.
Since the conventional hard disk drive is not provided with a unit for filtering the external air, fine dust particles contained in the air flow in the drive. The fine dust particles flowing in the drive adhere to the read/write head and the disk or float in an interior of the drive. As such, the fine dust particles cause thermal asperity (TA). According to the thermal asperity, fine particles held between the head and the disk cause friction between the head and the disk, so that the temperatures of the head and disk are abruptly raised to several hundreds degrees centigrade for a very short time. If the temperatures of the head and disk are raised, physical properties of the head and disk are varied, and scratch is generated on the disk. As a result, the performance of the hard disk drive is deteriorated. Therefore, it is necessary to eliminate the fine particles.